[PATCH] r/o bind mounts: get write access for vfs_rename() callers
This also uses the little helper in the NFS code to make an if() a little bit
less ugly. We introduced the helper at the beginning of the series.
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namei.c b/fs/namei.c
index 00df735..83c843b 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2718,8 +2718,12 @@
if (new_dentry == trap)
goto exit5;
+ error = mnt_want_write(oldnd.path.mnt);
+ if (error)
+ goto exit5;
error = vfs_rename(old_dir->d_inode, old_dentry,
new_dir->d_inode, new_dentry);
+ mnt_drop_write(oldnd.path.mnt);
exit5:
dput(new_dentry);
exit4:
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 71f8994..18a4cc9 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1710,13 +1710,20 @@
if (ndentry == trap)
goto out_dput_new;
-#ifdef MSNFS
- if ((ffhp->fh_export->ex_flags & NFSEXP_MSNFS) &&
+ if (svc_msnfs(ffhp) &&
((atomic_read(&odentry->d_count) > 1)
|| (atomic_read(&ndentry->d_count) > 1))) {
host_err = -EPERM;
- } else
-#endif
+ goto out_dput_new;
+ }
+
+ host_err = -EXDEV;
+ if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt)
+ goto out_dput_new;
+ host_err = mnt_want_write(ffhp->fh_export->ex_path.mnt);
+ if (host_err)
+ goto out_dput_new;
+
host_err = vfs_rename(fdir, odentry, tdir, ndentry);
if (!host_err && EX_ISSYNC(tfhp->fh_export)) {
host_err = nfsd_sync_dir(tdentry);
@@ -1724,6 +1731,8 @@
host_err = nfsd_sync_dir(fdentry);
}
+ mnt_drop_write(ffhp->fh_export->ex_path.mnt);
+
out_dput_new:
dput(ndentry);
out_dput_old: